Lawn care, mildew on sweet peas and bizzie lizzie care

Readers ask about problems with sweet peas, bizzie lizzies and lawns

Chris Lewis, from Kenilworth, wants to know why his/her sweet peas always get grey blotches on their leaves, which shortens their life? This is a form of mildew that almost always gets sweet peas in the end, because we always like to grow them in such concentration, thereby ensuring that there is poor circulation of air around their top growth, and not quite enough water around their roots. So for next year, perhaps: fewer plants in a larger space, compost that is more moisture-retentive – and more frequent watering. There are systemic fungicides available, of course, but they would need to be applied before symptoms appear – it is a bit late once the plants have succumbed.

Sweet peas can be blighted by mildew: feeding and watering may help.

Ingrid Grisdale sent me a picture of a large nasty looking patch of green, jelly-like slime that appeared on her lawn last year. She was advised by her garden centre that it was a result of waterlogging and that she should spike her lawn and work sand into the affected area. This she did, but the slime came back again this year.

The slime is, in fact, a form of lichen – actually called dog lichen. And indeed the chaps at Ingrid's garden centre are barking up the right tree, because dog lichen is more likely to occur on damp, mossy lawns and unless she can change the soil conditions dramatically (more spiking, more sand etc), it is likely to come back every year when weather conditions suit it.

Several anguished readers have reported that their busy lizzies were completely wiped out this year by a fungal disease. This happened last year, and the RHS boffs assured me that it was all the fault of Johnny Foreigner – the disease came from imported stock – but that it was unlikely to be as bad this year.

Well it seems to have been just as bad, if not worse – judging by my mail bag. To be fair, the RHS also said it would be a good idea to buy busy lizzie plants early in the season, so that they would be less likely to have lingered long in steamy polytunnels. So the answer would seem to be to get out there and do your shopping earlier next year.